import execjs
def get_js(self):
    with open(r"po.js") as f:
        line=f.readline()
        htmlstr=''
        while line:
            htmlstr=htmlstr+line
            line=f.readline()
        ctx=execjs.compile(htmlstr)
        return ctx.call('get_as_cp_signature')

sign=get_js()
print(sign)